NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Alternate methods of sight reduction
From: Nels Tomlinson
Date: 2005 Dec 7, 02:30 -0500
From: Nels Tomlinson
Date: 2005 Dec 7, 02:30 -0500
Zvi, I'd be very interested in seeing the scales, or the software, or both. Mostly the scales, I guess, since I'd like to make a working model myself. Could you email them to me, or post them somewhere? Thanks, Nels On 12/7/05, Zvi Doronwrote: > > Hi Jim > > I must run so it will be short - sorry > > I have studied the Bygrave slide rule and built several working models > including developing a piece of software to draw the scales - to my mind the > Bygrave is the most practical way of reducing a sight for a small boat where > accuracy of 1 mile is perfectly acceptable. > > Kind regards > > Zvi > > ----- Original Message ----- > From: Jim Hickey > To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM > > Sent: 06 December 2005 20:47 > Subject: Alternate methods of sight reduction > > > > > Alternate methods of sight reduction > > First, allow me to introduce myself as a new member. My name is Jim Hickey. > My wife Judy and I currently live aboard our sailboat in St. Augustine, > Florida. I have been interested in celestial navigation for many years much > to the amusement and entertainment of my wife! Even got the programming bug > early on but have it under reasonable control at this time. It has been a > delight to read many of the fascinating postings for some time now. > > I have a volume of Bowditch that discusses a variety of sight reduction > methods. I believe all the old table methods and more have been discussed. > Has anyone had access to or knowledge of the old slide rule type method that > is referenced? I believe the instrument was called a Bygrave computer which > looked cylindrical. > > As well, there is also a picture of a wonderfully elegant looking globe like > device that is set up with sliding arms that solves the navigational > triangle directly. > > I have been intrigued by these items for years and of course would love to > mess with them if I had the chance as I am sure many here would. > > Very curious to know how effective these approaches were and if there are > others etc. etc. > > Cheers, > > Jim